Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description exceeds the annotations' minimal safety hints by revealing critical behaviors: invoke works even when the MCP is not installed, returns a connect link if credentials are needed, and returns a checkout/top-up link for paid tools with an empty wallet. It also discloses that writes (install/uninstall/subscribe/cancel and the one-off install behind invoke) require workspace owner/admin, and that search/describe flag installation status.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single dense paragraph covering a large, multi-action tool. It is front-loaded with the core purpose and flow, then expands into prompts and permissions. Every sentence adds value, but the lack of bullet points or section breaks makes it harder to scan. It is appropriately sizable for a 14-action tool, though borderline verbose.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a tool with 14 actions, 23 parameters, and no output schema, the description provides a remarkably complete operational picture. It covers discovery, execution, installation, billing, permissions, auth, one-off behavior, and the prompt library. An agent can correctly select actions and understand the primary workflows, edge cases (credential/checkout), and authorization constraints without external documentation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With 0% schema description coverage, the description carries the burden of explaining parameters. It clarifies the action enum values (search, describe, install, invoke, list_tools, subscribe/cancel, report_bug, request_mcp, and prompt-related actions), and mentions tool_id, but leaves several parameters (e.g., immediate, tier_slug, cancel_reason, prompt_vars, conversation) unexplained. The description meaningfully compensates for the schema gap but not fully.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with 'The official mcp.ai marketplace — the in-platform catalog of every MCP/tool, AND the way to run them,' which clearly defines the tool's dual role. It explicitly differentiates from sibling tools (e.g., openfinance_* and authenticate) by positioning itself as the central hub for finding, describing, invoking, and installing MCPs, plus prompt management.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives explicit when-to-use guidance: 'Core flow: action=search discovers MCPs by intent → describe returns one MCP's full profile... so you pick the right tool_id → invoke RUNS that tool.' It further states 'Use install only to make an MCP PERMANENT' and 'prefer invoke for a single/occasional use,' directly advising on alternative actions. It also covers when to use list_tools, subscribe/cancel, and the prompt-library functions.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.